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qemu/linux-user/sparc/signal.c
Peter Maydell bba390cb9e linux-user/sparc/signal.c: Remove dead code 
Coverity complains (CID 1390847) about some dead code in
do_sigreturn(). This is an if (err) clause that can never be
true, copied from the kernel (where __get_user returns an error).
The one code path that could report an error is in the
currently commented-out pseudocode for handling FPU register
restoring, so move the if into that comment (and fix the
broken indent in the comment in the process).

(The new position for the error check is also the semantically
correct one -- we should not restore the signal mask from
the signal frame if we get an error here, so the check must
be done before set_sigmask(), not after.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-id: 20181115114616.26265-1-peter.maydell@linaro.org
2018-11-15 13:06:40 +00:00

628 lines
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/*
* Emulation of Linux signals
*
* Copyright (c) 2003 Fabrice Bellard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu.h"
#include "signal-common.h"
#include "linux-user/trace.h"
#define __SUNOS_MAXWIN 31
/* This is what SunOS does, so shall I. */
struct target_sigcontext {
abi_ulong sigc_onstack; /* state to restore */
abi_ulong sigc_mask; /* sigmask to restore */
abi_ulong sigc_sp; /* stack pointer */
abi_ulong sigc_pc; /* program counter */
abi_ulong sigc_npc; /* next program counter */
abi_ulong sigc_psr; /* for condition codes etc */
abi_ulong sigc_g1; /* User uses these two registers */
abi_ulong sigc_o0; /* within the trampoline code. */
/* Now comes information regarding the users window set
* at the time of the signal.
*/
abi_ulong sigc_oswins; /* outstanding windows */
/* stack ptrs for each regwin buf */
char *sigc_spbuf[__SUNOS_MAXWIN];
/* Windows to restore after signal */
struct {
abi_ulong locals[8];
abi_ulong ins[8];
} sigc_wbuf[__SUNOS_MAXWIN];
};
/* A Sparc stack frame */
struct sparc_stackf {
abi_ulong locals[8];
abi_ulong ins[8];
/* It's simpler to treat fp and callers_pc as elements of ins[]
* since we never need to access them ourselves.
*/
char *structptr;
abi_ulong xargs[6];
abi_ulong xxargs[1];
};
typedef struct {
struct {
abi_ulong psr;
abi_ulong pc;
abi_ulong npc;
abi_ulong y;
abi_ulong u_regs[16]; /* globals and ins */
} si_regs;
int si_mask;
} __siginfo_t;
typedef struct {
abi_ulong si_float_regs[32];
unsigned long si_fsr;
unsigned long si_fpqdepth;
struct {
unsigned long *insn_addr;
unsigned long insn;
} si_fpqueue [16];
} qemu_siginfo_fpu_t;
struct target_signal_frame {
struct sparc_stackf ss;
__siginfo_t info;
abi_ulong fpu_save;
abi_ulong insns[2] __attribute__ ((aligned (8)));
abi_ulong extramask[TARGET_NSIG_WORDS - 1];
abi_ulong extra_size; /* Should be 0 */
qemu_siginfo_fpu_t fpu_state;
};
struct target_rt_signal_frame {
struct sparc_stackf ss;
siginfo_t info;
abi_ulong regs[20];
sigset_t mask;
abi_ulong fpu_save;
unsigned int insns[2];
stack_t stack;
unsigned int extra_size; /* Should be 0 */
qemu_siginfo_fpu_t fpu_state;
};
#define UREG_O0 16
#define UREG_O6 22
#define UREG_I0 0
#define UREG_I1 1
#define UREG_I2 2
#define UREG_I3 3
#define UREG_I4 4
#define UREG_I5 5
#define UREG_I6 6
#define UREG_I7 7
#define UREG_L0 8
#define UREG_FP UREG_I6
#define UREG_SP UREG_O6
static inline abi_ulong get_sigframe(struct target_sigaction *sa,
CPUSPARCState *env,
unsigned long framesize)
{
abi_ulong sp = get_sp_from_cpustate(env);
/*
* If we are on the alternate signal stack and would overflow it, don't.
* Return an always-bogus address instead so we will die with SIGSEGV.
*/
if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) {
return -1;
}
/* This is the X/Open sanctioned signal stack switching. */
sp = target_sigsp(sp, sa) - framesize;
/* Always align the stack frame. This handles two cases. First,
* sigaltstack need not be mindful of platform specific stack
* alignment. Second, if we took this signal because the stack
* is not aligned properly, we'd like to take the signal cleanly
* and report that.
*/
sp &= ~15UL;
return sp;
}
static int
setup___siginfo(__siginfo_t *si, CPUSPARCState *env, abi_ulong mask)
{
int err = 0, i;
__put_user(env->psr, &si->si_regs.psr);
__put_user(env->pc, &si->si_regs.pc);
__put_user(env->npc, &si->si_regs.npc);
__put_user(env->y, &si->si_regs.y);
for (i=0; i < 8; i++) {
__put_user(env->gregs[i], &si->si_regs.u_regs[i]);
}
for (i=0; i < 8; i++) {
__put_user(env->regwptr[UREG_I0 + i], &si->si_regs.u_regs[i+8]);
}
__put_user(mask, &si->si_mask);
return err;
}
#if 0
static int
setup_sigcontext(struct target_sigcontext *sc, /*struct _fpstate *fpstate,*/
CPUSPARCState *env, unsigned long mask)
{
int err = 0;
__put_user(mask, &sc->sigc_mask);
__put_user(env->regwptr[UREG_SP], &sc->sigc_sp);
__put_user(env->pc, &sc->sigc_pc);
__put_user(env->npc, &sc->sigc_npc);
__put_user(env->psr, &sc->sigc_psr);
__put_user(env->gregs[1], &sc->sigc_g1);
__put_user(env->regwptr[UREG_O0], &sc->sigc_o0);
return err;
}
#endif
#define NF_ALIGNEDSZ (((sizeof(struct target_signal_frame) + 7) & (~7)))
void setup_frame(int sig, struct target_sigaction *ka,
target_sigset_t *set, CPUSPARCState *env)
{
abi_ulong sf_addr;
struct target_signal_frame *sf;
int sigframe_size, err, i;
/* 1. Make sure everything is clean */
//synchronize_user_stack();
sigframe_size = NF_ALIGNEDSZ;
sf_addr = get_sigframe(ka, env, sigframe_size);
trace_user_setup_frame(env, sf_addr);
sf = lock_user(VERIFY_WRITE, sf_addr,
sizeof(struct target_signal_frame), 0);
if (!sf) {
goto sigsegv;
}
#if 0
if (invalid_frame_pointer(sf, sigframe_size))
goto sigill_and_return;
#endif
/* 2. Save the current process state */
err = setup___siginfo(&sf->info, env, set->sig[0]);
__put_user(0, &sf->extra_size);
//save_fpu_state(regs, &sf->fpu_state);
//__put_user(&sf->fpu_state, &sf->fpu_save);
__put_user(set->sig[0], &sf->info.si_mask);
for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
__put_user(set->sig[i + 1], &sf->extramask[i]);
}
for (i = 0; i < 8; i++) {
__put_user(env->regwptr[i + UREG_L0], &sf->ss.locals[i]);
}
for (i = 0; i < 8; i++) {
__put_user(env->regwptr[i + UREG_I0], &sf->ss.ins[i]);
}
if (err)
goto sigsegv;
/* 3. signal handler back-trampoline and parameters */
env->regwptr[UREG_FP] = sf_addr;
env->regwptr[UREG_I0] = sig;
env->regwptr[UREG_I1] = sf_addr +
offsetof(struct target_signal_frame, info);
env->regwptr[UREG_I2] = sf_addr +
offsetof(struct target_signal_frame, info);
/* 4. signal handler */
env->pc = ka->_sa_handler;
env->npc = (env->pc + 4);
/* 5. return to kernel instructions */
if (ka->ka_restorer) {
env->regwptr[UREG_I7] = ka->ka_restorer;
} else {
uint32_t val32;
env->regwptr[UREG_I7] = sf_addr +
offsetof(struct target_signal_frame, insns) - 2 * 4;
/* mov __NR_sigreturn, %g1 */
val32 = 0x821020d8;
__put_user(val32, &sf->insns[0]);
/* t 0x10 */
val32 = 0x91d02010;
__put_user(val32, &sf->insns[1]);
}
unlock_user(sf, sf_addr, sizeof(struct target_signal_frame));
return;
#if 0
sigill_and_return:
force_sig(TARGET_SIGILL);
#endif
sigsegv:
unlock_user(sf, sf_addr, sizeof(struct target_signal_frame));
force_sigsegv(sig);
}
void setup_rt_frame(int sig, struct target_sigaction *ka,
target_siginfo_t *info,
target_sigset_t *set, CPUSPARCState *env)
{
qemu_log_mask(LOG_UNIMP, "setup_rt_frame: not implemented\n");
}
long do_sigreturn(CPUSPARCState *env)
{
abi_ulong sf_addr;
struct target_signal_frame *sf;
uint32_t up_psr, pc, npc;
target_sigset_t set;
sigset_t host_set;
int i;
sf_addr = env->regwptr[UREG_FP];
trace_user_do_sigreturn(env, sf_addr);
if (!lock_user_struct(VERIFY_READ, sf, sf_addr, 1)) {
goto segv_and_exit;
}
/* 1. Make sure we are not getting garbage from the user */
if (sf_addr & 3)
goto segv_and_exit;
__get_user(pc, &sf->info.si_regs.pc);
__get_user(npc, &sf->info.si_regs.npc);
if ((pc | npc) & 3) {
goto segv_and_exit;
}
/* 2. Restore the state */
__get_user(up_psr, &sf->info.si_regs.psr);
/* User can only change condition codes and FPU enabling in %psr. */
env->psr = (up_psr & (PSR_ICC /* | PSR_EF */))
| (env->psr & ~(PSR_ICC /* | PSR_EF */));
env->pc = pc;
env->npc = npc;
__get_user(env->y, &sf->info.si_regs.y);
for (i=0; i < 8; i++) {
__get_user(env->gregs[i], &sf->info.si_regs.u_regs[i]);
}
for (i=0; i < 8; i++) {
__get_user(env->regwptr[i + UREG_I0], &sf->info.si_regs.u_regs[i+8]);
}
/* FIXME: implement FPU save/restore:
* __get_user(fpu_save, &sf->fpu_save);
* if (fpu_save) {
* if (restore_fpu_state(env, fpu_save)) {
* goto segv_and_exit;
* }
* }
*/
/* This is pretty much atomic, no amount locking would prevent
* the races which exist anyways.
*/
__get_user(set.sig[0], &sf->info.si_mask);
for(i = 1; i < TARGET_NSIG_WORDS; i++) {
__get_user(set.sig[i], &sf->extramask[i - 1]);
}
target_to_host_sigset_internal(&host_set, &set);
set_sigmask(&host_set);
unlock_user_struct(sf, sf_addr, 0);
return -TARGET_QEMU_ESIGRETURN;
segv_and_exit:
unlock_user_struct(sf, sf_addr, 0);
force_sig(TARGET_SIGSEGV);
return -TARGET_QEMU_ESIGRETURN;
}
long do_rt_sigreturn(CPUSPARCState *env)
{
trace_user_do_rt_sigreturn(env, 0);
qemu_log_mask(LOG_UNIMP, "do_rt_sigreturn: not implemented\n");
return -TARGET_ENOSYS;
}
#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
#define SPARC_MC_TSTATE 0
#define SPARC_MC_PC 1
#define SPARC_MC_NPC 2
#define SPARC_MC_Y 3
#define SPARC_MC_G1 4
#define SPARC_MC_G2 5
#define SPARC_MC_G3 6
#define SPARC_MC_G4 7
#define SPARC_MC_G5 8
#define SPARC_MC_G6 9
#define SPARC_MC_G7 10
#define SPARC_MC_O0 11
#define SPARC_MC_O1 12
#define SPARC_MC_O2 13
#define SPARC_MC_O3 14
#define SPARC_MC_O4 15
#define SPARC_MC_O5 16
#define SPARC_MC_O6 17
#define SPARC_MC_O7 18
#define SPARC_MC_NGREG 19
typedef abi_ulong target_mc_greg_t;
typedef target_mc_greg_t target_mc_gregset_t[SPARC_MC_NGREG];
struct target_mc_fq {
abi_ulong *mcfq_addr;
uint32_t mcfq_insn;
};
struct target_mc_fpu {
union {
uint32_t sregs[32];
uint64_t dregs[32];
//uint128_t qregs[16];
} mcfpu_fregs;
abi_ulong mcfpu_fsr;
abi_ulong mcfpu_fprs;
abi_ulong mcfpu_gsr;
struct target_mc_fq *mcfpu_fq;
unsigned char mcfpu_qcnt;
unsigned char mcfpu_qentsz;
unsigned char mcfpu_enab;
};
typedef struct target_mc_fpu target_mc_fpu_t;
typedef struct {
target_mc_gregset_t mc_gregs;
target_mc_greg_t mc_fp;
target_mc_greg_t mc_i7;
target_mc_fpu_t mc_fpregs;
} target_mcontext_t;
struct target_ucontext {
struct target_ucontext *tuc_link;
abi_ulong tuc_flags;
target_sigset_t tuc_sigmask;
target_mcontext_t tuc_mcontext;
};
/* A V9 register window */
struct target_reg_window {
abi_ulong locals[8];
abi_ulong ins[8];
};
#define TARGET_STACK_BIAS 2047
/* {set, get}context() needed for 64-bit SparcLinux userland. */
void sparc64_set_context(CPUSPARCState *env)
{
abi_ulong ucp_addr;
struct target_ucontext *ucp;
target_mc_gregset_t *grp;
abi_ulong pc, npc, tstate;
abi_ulong fp, i7, w_addr;
unsigned int i;
ucp_addr = env->regwptr[UREG_I0];
if (!lock_user_struct(VERIFY_READ, ucp, ucp_addr, 1)) {
goto do_sigsegv;
}
grp = &ucp->tuc_mcontext.mc_gregs;
__get_user(pc, &((*grp)[SPARC_MC_PC]));
__get_user(npc, &((*grp)[SPARC_MC_NPC]));
if ((pc | npc) & 3) {
goto do_sigsegv;
}
if (env->regwptr[UREG_I1]) {
target_sigset_t target_set;
sigset_t set;
if (TARGET_NSIG_WORDS == 1) {
__get_user(target_set.sig[0], &ucp->tuc_sigmask.sig[0]);
} else {
abi_ulong *src, *dst;
src = ucp->tuc_sigmask.sig;
dst = target_set.sig;
for (i = 0; i < TARGET_NSIG_WORDS; i++, dst++, src++) {
__get_user(*dst, src);
}
}
target_to_host_sigset_internal(&set, &target_set);
set_sigmask(&set);
}
env->pc = pc;
env->npc = npc;
__get_user(env->y, &((*grp)[SPARC_MC_Y]));
__get_user(tstate, &((*grp)[SPARC_MC_TSTATE]));
env->asi = (tstate >> 24) & 0xff;
cpu_put_ccr(env, tstate >> 32);
cpu_put_cwp64(env, tstate & 0x1f);
__get_user(env->gregs[1], (&(*grp)[SPARC_MC_G1]));
__get_user(env->gregs[2], (&(*grp)[SPARC_MC_G2]));
__get_user(env->gregs[3], (&(*grp)[SPARC_MC_G3]));
__get_user(env->gregs[4], (&(*grp)[SPARC_MC_G4]));
__get_user(env->gregs[5], (&(*grp)[SPARC_MC_G5]));
__get_user(env->gregs[6], (&(*grp)[SPARC_MC_G6]));
__get_user(env->gregs[7], (&(*grp)[SPARC_MC_G7]));
__get_user(env->regwptr[UREG_I0], (&(*grp)[SPARC_MC_O0]));
__get_user(env->regwptr[UREG_I1], (&(*grp)[SPARC_MC_O1]));
__get_user(env->regwptr[UREG_I2], (&(*grp)[SPARC_MC_O2]));
__get_user(env->regwptr[UREG_I3], (&(*grp)[SPARC_MC_O3]));
__get_user(env->regwptr[UREG_I4], (&(*grp)[SPARC_MC_O4]));
__get_user(env->regwptr[UREG_I5], (&(*grp)[SPARC_MC_O5]));
__get_user(env->regwptr[UREG_I6], (&(*grp)[SPARC_MC_O6]));
__get_user(env->regwptr[UREG_I7], (&(*grp)[SPARC_MC_O7]));
__get_user(fp, &(ucp->tuc_mcontext.mc_fp));
__get_user(i7, &(ucp->tuc_mcontext.mc_i7));
w_addr = TARGET_STACK_BIAS+env->regwptr[UREG_I6];
if (put_user(fp, w_addr + offsetof(struct target_reg_window, ins[6]),
abi_ulong) != 0) {
goto do_sigsegv;
}
if (put_user(i7, w_addr + offsetof(struct target_reg_window, ins[7]),
abi_ulong) != 0) {
goto do_sigsegv;
}
/* FIXME this does not match how the kernel handles the FPU in
* its sparc64_set_context implementation. In particular the FPU
* is only restored if fenab is non-zero in:
* __get_user(fenab, &(ucp->tuc_mcontext.mc_fpregs.mcfpu_enab));
*/
__get_user(env->fprs, &(ucp->tuc_mcontext.mc_fpregs.mcfpu_fprs));
{
uint32_t *src = ucp->tuc_mcontext.mc_fpregs.mcfpu_fregs.sregs;
for (i = 0; i < 64; i++, src++) {
if (i & 1) {
__get_user(env->fpr[i/2].l.lower, src);
} else {
__get_user(env->fpr[i/2].l.upper, src);
}
}
}
__get_user(env->fsr,
&(ucp->tuc_mcontext.mc_fpregs.mcfpu_fsr));
__get_user(env->gsr,
&(ucp->tuc_mcontext.mc_fpregs.mcfpu_gsr));
unlock_user_struct(ucp, ucp_addr, 0);
return;
do_sigsegv:
unlock_user_struct(ucp, ucp_addr, 0);
force_sig(TARGET_SIGSEGV);
}
void sparc64_get_context(CPUSPARCState *env)
{
abi_ulong ucp_addr;
struct target_ucontext *ucp;
target_mc_gregset_t *grp;
target_mcontext_t *mcp;
abi_ulong fp, i7, w_addr;
int err;
unsigned int i;
target_sigset_t target_set;
sigset_t set;
ucp_addr = env->regwptr[UREG_I0];
if (!lock_user_struct(VERIFY_WRITE, ucp, ucp_addr, 0)) {
goto do_sigsegv;
}
mcp = &ucp->tuc_mcontext;
grp = &mcp->mc_gregs;
/* Skip over the trap instruction, first. */
env->pc = env->npc;
env->npc += 4;
/* If we're only reading the signal mask then do_sigprocmask()
* is guaranteed not to fail, which is important because we don't
* have any way to signal a failure or restart this operation since
* this is not a normal syscall.
*/
err = do_sigprocmask(0, NULL, &set);
assert(err == 0);
host_to_target_sigset_internal(&target_set, &set);
if (TARGET_NSIG_WORDS == 1) {
__put_user(target_set.sig[0],
(abi_ulong *)&ucp->tuc_sigmask);
} else {
abi_ulong *src, *dst;
src = target_set.sig;
dst = ucp->tuc_sigmask.sig;
for (i = 0; i < TARGET_NSIG_WORDS; i++, dst++, src++) {
__put_user(*src, dst);
}
if (err)
goto do_sigsegv;
}
/* XXX: tstate must be saved properly */
// __put_user(env->tstate, &((*grp)[SPARC_MC_TSTATE]));
__put_user(env->pc, &((*grp)[SPARC_MC_PC]));
__put_user(env->npc, &((*grp)[SPARC_MC_NPC]));
__put_user(env->y, &((*grp)[SPARC_MC_Y]));
__put_user(env->gregs[1], &((*grp)[SPARC_MC_G1]));
__put_user(env->gregs[2], &((*grp)[SPARC_MC_G2]));
__put_user(env->gregs[3], &((*grp)[SPARC_MC_G3]));
__put_user(env->gregs[4], &((*grp)[SPARC_MC_G4]));
__put_user(env->gregs[5], &((*grp)[SPARC_MC_G5]));
__put_user(env->gregs[6], &((*grp)[SPARC_MC_G6]));
__put_user(env->gregs[7], &((*grp)[SPARC_MC_G7]));
__put_user(env->regwptr[UREG_I0], &((*grp)[SPARC_MC_O0]));
__put_user(env->regwptr[UREG_I1], &((*grp)[SPARC_MC_O1]));
__put_user(env->regwptr[UREG_I2], &((*grp)[SPARC_MC_O2]));
__put_user(env->regwptr[UREG_I3], &((*grp)[SPARC_MC_O3]));
__put_user(env->regwptr[UREG_I4], &((*grp)[SPARC_MC_O4]));
__put_user(env->regwptr[UREG_I5], &((*grp)[SPARC_MC_O5]));
__put_user(env->regwptr[UREG_I6], &((*grp)[SPARC_MC_O6]));
__put_user(env->regwptr[UREG_I7], &((*grp)[SPARC_MC_O7]));
w_addr = TARGET_STACK_BIAS+env->regwptr[UREG_I6];
fp = i7 = 0;
if (get_user(fp, w_addr + offsetof(struct target_reg_window, ins[6]),
abi_ulong) != 0) {
goto do_sigsegv;
}
if (get_user(i7, w_addr + offsetof(struct target_reg_window, ins[7]),
abi_ulong) != 0) {
goto do_sigsegv;
}
__put_user(fp, &(mcp->mc_fp));
__put_user(i7, &(mcp->mc_i7));
{
uint32_t *dst = ucp->tuc_mcontext.mc_fpregs.mcfpu_fregs.sregs;
for (i = 0; i < 64; i++, dst++) {
if (i & 1) {
__put_user(env->fpr[i/2].l.lower, dst);
} else {
__put_user(env->fpr[i/2].l.upper, dst);
}
}
}
__put_user(env->fsr, &(mcp->mc_fpregs.mcfpu_fsr));
__put_user(env->gsr, &(mcp->mc_fpregs.mcfpu_gsr));
__put_user(env->fprs, &(mcp->mc_fpregs.mcfpu_fprs));
if (err)
goto do_sigsegv;
unlock_user_struct(ucp, ucp_addr, 1);
return;
do_sigsegv:
unlock_user_struct(ucp, ucp_addr, 1);
force_sig(TARGET_SIGSEGV);
}
#endif
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